Pyrotechnic circuit maker or breaker

ABSTRACT

A pyrotechnic device designed to irreversibly make or break a permanent electrical contact as controlled by an initial electrical, mechanical or pyrotechnic signal, the device comprising an elastomer head mounted on the pyrotechnic cartridge and containing a hollow interior portion in which two electrical contact members are disposed, a deformable partition separating the pyrotechnic charge from the elastomer body, and a member which is moved into contact with the two contact elements to either make or break an electrical connection between the two contacts depending upon whether the third element is composed of conducting or insulating material.

United States Patent [1 1 Delgendre et a1.

1111 3,803,374 1451 Apr. 9, 1974 PYROTECHNIC CIRCUIT MAKER 0R BREAKER I [75] Inventors: Jacques Claude Delgendre, Toulon;

Vincent Louis Eugene Guigot, La Seyne Sur Mer, both of France [73] Assignee: LEtat Francais Delegation Ministerielle Pour LArmement Direction Technique des Armements Terrestres, Paris, France 22 Filed: Oct. 27, 1972 21 Appl. No.: 301,534

[30] Foreign Application'Priority Data Nov. 5, 1971 France 71.39783 [521 US. Cl ZOO/61.08, 200/6l.19, 200/83 N [51] Int. Cl. H0lh 39/00 [58] Field of Search 200/6108, 61.19, 61.8, 200/83 N; 337/114, 401

[5 6] References Cited UNITED STATES PATENTS 3,277,255 10/1966 Mattsson et a1. ZOO/61.08 2,697,766

12/1954 Goldmuntz 200/83 N X 2,768,261 10/1956 Mathisen 200/83 N 3,264,438 8/1966 Gay ZOO/61.08 X 3,335,239 8/1967 Fey ZOO/61.08 2,999,912 12/1961 Kincaid et a1 200/618 X 3,049,601 8/1962 Hardesty ZOO/61.08 X 2,511,955 6/1950 West ZOO/61.19 X

Primary Examiner.lames R. Scott Attorney, Agent, or FirmStevens, Davis, Miller & Mosher [57] ABSTRACT A pyrotechnic device designed to irreversibly make or break a permanent electrical contact as controlled by an initial electrical, mechanical or pyrotechnic signal, the device comprising an elastomer head mounted on the pyrotechnic cartridge and containing a hollow interior portion in which two electrical contact members are disposed, a deformable partition separating the pyrotechnic charge from the elastomer body, and a member which is moved into contact ,with the two contact elements to either make or break an electrical connection'between the two contacts depending upon whether the third element is composed of conducting or insulating material.

3 Claims, 5 Drawing Figures PATENTEDAPR 9 1914 FIG.3

sum 2 or 2 FIG.4

The present invention relates to a device intended to make or break a permanent electrical contact using a pyrotechnic element triggered by electrical, mechanical or pyrotechnic means.

It is common knowledge that pyrotechnic switches have a number of advantages compared to electromagnetic switches: absence of external powersource, low weight, fast operation speed, resistance against environmental conditions. The making of the contact, however, and the transmission of theenergy supplied by the pyrotechnic element, or at least thefirst of these functions, is performed by the rotational or linear motion of mechanical parts.'This design leads to a certain complexity prejudicial to reliability and restricting the miniaturization possibilities while also rendering the switch sensitive to shock and vibration.

The device according to this invention enables thesedrawbacks to be overcome, since making of contact-.-

and energy transmission takes place solely through non-elastic deformation, no part being affected by an overall motion.Moreover, the simplicity of, the switch results in a significantly. lower production cost and, as the inertia of the operating parts is very small, the operating time can thus be reduced.

The invention resides in a pyrotechnic device designed to irreversibly and permanently make or break an electrical contact wh'en initiated by an electrical, mechanical or pyrotechnical signal. The device is characterized by the fact that it housesthe following elements in a singleshell: a hollow elastomer insert carrying two metal conducting elements, each connected to one of two connecting pins; a pyrotechnic element separated from the insert by a deformable partition, the

pyrotechnic element when energized by an electrical, mechanical or pyrotechnic source actsto make or break the electrical contact between the two'metal conducting elements. In one embodiment, theinvention described herein is employed asa switch in which electrical contactbetween the two conducting elements is a third electrically conducting element brought'into contact with the first two metal conducting elements by deformationof thepartition. I I I r i In a second embodiment, t he invention is used as a circuit-breaker;the preestablished contact between the two conducting elements is broken by an insulating element which is inserted between't he two conducting elements by the deformation of the partition.'

The invention will be described below with reference to the appended drawing, wherein:

rated, as by molding. Part 3 is a ring whereas parts 4 and 5 are half-rings insulated from each other. Parts 4 and 5 are connected to connecting pins 7 which extend through and out of body 1 via sealed insulating bushings 6.-

A pyrotechnic cartridge 8 is screwed into body I with deformable partition 18 in between. This cartridge contains an explosive charge and an electrical pyrotechnic squib 10 fitted with connecting pins 11 which extend through and out of the cartridge via a sealed insulating bushing 12.

The above device operates as follows: on application of an appropriate electrical signal, charge 9 explodes, thereby deforming partition 18 by an amount greater than the space provided between the contact elements when in rest position. Part 3 is therefore pressed against parts 2, being compressed, ensures contact despite opposing forces, especially vibratory, which would be exerted upon the metal parts.

In other practical applications of the invention, the

' explosion is initiated through other means, e.g. percussion or transmission bya detonating fuse. The shape of the metal contact elements can also vary, e.g. for the purpose of simultaneously closing several circuits.

FIG. 2 shows the portion of the circuit breaker embodiment of this invention which differs from that of the switch, or circuit maker, embodiment described above. In both devices, the head or'body portion 1 (of the circuit maker) and 1' (of thecirc uit breaker) are screwed onto the pyrotechnic cartridge 8. In the circuit breaker, metal studs 15 and 16 are molded into the elastomer hollow body 1 and are connected to pins 7 which extend out of the body through sealed insulating bushings 6'. Studs 15 and 16 support rectangularly shaped contact blades 13 and 14. The free ends of blades 13 and 14 have U-shaped cutouts which overlap in-opposed fashion to form a circular opening 19 see FIG. 2a) into which the tip of a conical punch 17 is in- FIG. 1 shows a sectional view of the circuit maker embodiment with'contacts in a normally open position;

FIG. 2shows asectional'view of the circuit breaker embodiment withcontacts a'normally'closed posi- FIG. 2a shows adetail of the contac't elements of the" circuit breaker embodiment; FIG. 3 shows'a sectionalview of the circuit maker embodiment with contacts in a closed position; and

* FIG. 4 shows a sectional view of the circuit breaker embodiment with contacts in an open position.

In the embodiment of FIG. 1, a'body 1 houses the switch proper which consists ofa hollow elastomerinsert 2 into which metal parts 3, 4 and Sare incorpo ing the contacts and where the mechanical or climatic serted. The punch 17 is tightly'fitted to the bottom of the body 1' to form a surface on which the deformable partition 18' rests when the body is assembled onto the cartridge8, as shown.

The device above operates as follows: deformation of partition 18 in the manner described previously causes the deformation of the elastomer box bottom, and punch 17, which is fastened to that bottom, is forced upwardly in the direction of deformation of partition 18, breaking the contact between the blades 13 and 14 which then are irreversibly insulated bythe insulating material of the punch wedged between these two contact elements.

The device according to the invention can be used whenever a permanent electrical contact is to be made or broken as controlled by an electrical or mechanical signal. It is of particular value in the case where an external powersource is not available for closing or openenvironment precludes the use of-electromagnetic or solid-state switches and relays; For these reasons, the

device is particularly useful for performing logic operav tions or electrical controls in sequential systems which are to be operated once only," as found on missiles, space launch vehicles, underwater fixtures, etc. A few examples can be mentioned, such as the arming and control of the ignition circuit of power plants, the separation of stages, the opening of valves and the energization'of electricalequipment carried by missiles.- l

What is claimed is:

l. A pyrotechnic device designed to irreversibly make or break a permanent electrical contact as controlled by an initial electrical, mechanical or pyrotechnic signal, comprising: a cartridge having a cavity containing a pyrotechnic charge and means to detonate said charge; an elastomer body disposed on said carnation of the said pyrotechnic charge.

2. The device according to claim 1, wherein said third element comprises an electrically conducting member which, when urged into contact with said first and second elements upon deformation of said partition, completes an electrical circuit between said first and second elements. g

3. The device according to claim 1, wherein said third element comprises an insulating member which, when urged into engagement with said first and second contact elements upon deformation of said partition, separates said first and second elements from contact with each other to thereby break a pre-existing completed electrical circuit between said first and second elements. I 

1. A pyrotechnic device designed to irreversibly make or break a permanent electrical contact as controlled by an initial electrical, mechanical or pyrotechnic signal, comprising: a cartridge having a cavity containing a pyrotechnic charge and means to detonate said charge; an elastomer body disposed on said cartridge; first and second metal contact elements disposed in an interior cavity of said body and connected to external electrical terminals; a deformable partition separating the chargecontaining cavity of said cartridge and the hollow interior cavity of said elastomer body; and a third element resting on said deformable partition and located in said hollow interior cavity and urged into contact with said first and second contact elements when said partition is deformed by the detonation of the said pyrotechnic charge.
 2. The device according to claim 1, wherein said third element comprises an electrically conducting member which, when urged into contact with said first and second elements upon deformation of said partition, completes an electrical circuit between said first and second elements.
 3. The device according to claim 1, wherein said third element comprises an insulating member which, when urged into engagement with said first and second contact elements upon deformation of said partition, separates said first and second elements from contact with each other to thereby break a pre-existing completed electrical circuit between said first and second elements. 